The invention relates to a key device for use in typewriter, calculator, and other keyboards. In particular, it relates to a key device that provides a feedback control feeling to a key operator, so that efficient key operation may be accomplished.
In typewriter keyboards and the like, key devices are required which offer a certain resistance to operation, so that an operator may sense successful actuation of a desired key. This resistance to operation is generally referred to as the "touch" or "feel". A minimal key resistance allows for this feel without creating any difficulty in operation, which would result in loss of efficiency. A present method achieves this feel through mechanical friction means. However, such friction means are subject to constant wear, and in a system with a plurality of keys this wear is often uneven, resulting in a non-uniform resistance force for all the keys. Accordingly, delicate adjustment is often required. Additionally, the feel offered by a solely frictional feel control device is merely a constant resistance force, which is less conducive to ideal control feeling than a detectable force variation. Hence, for efficiency and ease of use, a key system is needed which provides for a good control feeling, including a variable resistance force for each key that is uniform for a plurality of keys.